| Description of Stock Plans - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified | 6 Months Ended | 1 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Sep. 30, 2012 | Sep. 10, 2012
 Before Amendment | Sep. 10, 2012
 After Amendment | Sep. 30, 2012
 2007 Employee, Director and Consultant Stock Plan equity compensation plan | Feb. 12, 2008
 2007 Employee, Director and Consultant Stock Plan equity compensation plan | Sep. 27, 2007
 2007 Employee, Director and Consultant Stock Plan equity compensation plan | Mar. 07, 2008
 2007 Employee, Director and Consultant Stock Plan equity compensation plan
 Any fiscal year | Sep. 27, 2007
 2007 Employee, Director and Consultant Stock Plan equity compensation plan
 Maximum | Sep. 30, 2012
 Stock Option Plan 2011 | May 23, 2012
 Stock Option Plan 2011 | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||||||
| Individual Grant Limits | 500,000 | |||||||||
| Maximum number of shares or equivalents of common stock that may be granted | 4,000,000 | 20,000,000 | 7,000,000 | 3,000,000 | 1,100 | |||||
| Shares reserved for future issuance | 20,000,000 | |||||||||
| Number of shares available for issuance | 15,916,667 | |||||||||
| Share Options Exercisable | 0 | 4,798,000 | ||||||||
| Option plan, term | 10 years | |||||||||
| Total unrecognized compensation cost related to nonvested share based compensation | $ 0 | |||||||||
| X | ||||||||||
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- Definition Number Of Shares Granted Against Share Limits No definition available. 
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| X | ||||||||||
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- Definition Aggregate number of common shares reserved for future issuance. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Details 
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| X | ||||||||||
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition Weighted average remaining contractual term for fully vested and expected to vest options that are exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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